Method and system for air straighteners for steam purging

Abstract

Method for controlling the operation of a power engine (21) with a fuel vapor purging system (18) comprising the following: Directing of intake air through a first throttle valve (44, T1) and an air funnel (47) arranged in a bypass line (502) coupled in parallel around a second throttle valve (67, T2) arranged in the intake; In response to an operating condition, a fuel vapor flow is supplied from the fuel vapor purge system (18) to an inlet of the air funnel (47); characterized by Adjusting the amount of fuel vapor flow supplied to the inlet of the air funnel (47) via a fuel vapor purge valve (98) coupled to the fuel vapor purge system (18), wherein the amount of fuel vapor flow supplied to the inlet of the air funnel (47) is adjusted on the basis of an air flow rate through the air funnel (47) and an air temperature and air pressure.

Description

[0001] Evaporative emission control systems trap fuel vapors in a canister, such as when a vehicle is parked, then combust the vapors in the engine when it is running. Some methods use a vacuum created in the engine's intake manifold to draw air through the canister to purge the fuel within. In some examples, such fuel vapor purge systems may be used on engines that include features to increase fuel economy, such as variable camshaft timing, variable valve lift, engine downsizing (e.g., EcoBoost), hybridization (e.g., in a hybrid electric vehicle (HEV), etc.).

[0002] However, such methods that increase fuel economy may decrease the amount of intake manifold vacuum and / or how frequently vacuum is available, thus decreasing the amount of vacuum available to purge fuel vapors from a fuel vapor purge system. Further, in some examples, when more purge vacuum is desired in such methods, fuel economy may be sacrificed to increase the vacuum for fuel purge, e.g., by forcing an engine restart in an HEV or by reducing the use of variable camshaft timing or variable valve lift. Some methods may use electric pumps for vapor purge to avoid this fuel economy penalty. However, such pumps can be expensive, and the electricity to operate them may increase parasitic loads that decrease fuel economy.Document US 2011 / 0 146 631 A1 discloses a device for treating evaporated fuel that collects the vapor generated in a fuel tank in a canister. Further prior art is known from DE 10 2011 078 993 A1 and DE 10 2011 003 034 A1.

[0003] In some methods, a venturi (referred to as an air horn) or aspirator may be coupled into an engine intake system, and a fuel vapor purge system or other systems requiring vacuum may be coupled to an inlet of the air horn so that vacuum created in the air horn can be delivered to the fuel vapor purge system or other vacuum system. However, the inventors have recognized problems with such methods. For example, an air horn coupled into an engine intake system may restrict flow, so that wide-open throttle performance may be degraded. Further, in such methods, the position of the air horn relative to a throttle body may degrade engine performance.For example, if an air horn is located downstream of a throttle body in an intake system, the air volume downstream of the throttle body may be increased, which may result in degraded transient torque response, particularly in turbocharged engines. As another example, if an air horn is located upstream of a throttle body in an intake system, an increase in throttle body deposits may occur in the throttle body if a fuel vapor purge system is coupled to an air horn inlet.

[0004] The object of the present invention is to provide improved methods and an improved system for a power machine.

[0005] This problem is solved by the features of the independent patent claims. Advantageous developments of the invention are the subject of the dependent claims.

[0006] In one example method, a method for controlling operation of an engine having a fuel vapor purge system includes: directing intake air through a first throttle and air funnel disposed in a bypass conduit coupled to an intake system of the engine upstream and downstream of a second throttle disposed in the intake system; and responsive to an operating condition, delivering a fuel vapor flow from the fuel vapor purge system to an inlet of the air funnel.

[0007] In this way, the air funnel or aspirator in the intake manifold can be used to increase the amount and availability of vacuum for fuel vapor purging, which can reduce component costs and increase fuel economy while providing sufficient vacuum for the vapor purging system, while reducing the impact on performance at wide open throttle, for example.

[0008] Of course, the above summary is provided to introduce, in a simplified form, a selection of concepts further described in the detailed description. It is not intended to identify key or essential features of the claimed subject matter, the scope of which is defined only by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that resolve any disadvantages identified above or in any part of this disclosure. Fig. 1 shows a schematic representation of an example vehicle with an engine system. Fig. 2 shows an example engine system. Fig. 3 - Fig. 5 illustrate example embodiments of an air horn coupled into an intake system of the engine, according to the disclosure. Fig. 6 - Fig. 7 illustrate example methods for controlling operation of an engine having a fuel vapor purge system according to the disclosure. Fig. 8 graphically illustrates example throttle settings in response to engine load changes according to the disclosure. Fig. 9 shows example throttle settings in response to pedal position changes according to the disclosure. Fig. 10 and Fig. 11 illustrate example methods for adjusting throttles during transient conditions in accordance with the disclosure.

[0009] The following description relates to systems and methods for operating an engine having a fuel vapor purge system such as those described in Fig. 1 - Fig. 2 systems. As in Fig. 3 - Fig. 5, an air horn or aspirator may be disposed in an intake system of the engine adjacent to a throttle valve, and a fuel vapor purge system may be coupled to the air horn so that a vacuum created by the air horn may be used during fuel purge events. As shown in Fig. 6 - Fig. 7, various methods may be used to purge fuel from the fuel vapor purge system using the vacuum created by the air funnel. Furthermore, throttle adjustments, for example, as shown in Fig. 8 - Fig. 11, in response to engine operating conditions to meet torque requirements while still providing vacuum to a fuel vapor purge system.

[0010] In Fig. 1, an example vehicle with a power engine is shown schematically. In some examples, as in Fig. 1, the vehicle may be a hybrid electric vehicle (HEV) and may include a hybrid propulsion system 10. However, in other examples, the vehicle may not be an HEV and may be powered only by an engine system 11.

[0011] The hybrid drive system 10 includes an internal combustion engine 21 coupled to a transmission 17. The transmission 17 may be a manual transmission, an automatic transmission, or a combination thereof. Various additional components may also be included, such as a torque converter and / or other gearing, such as a final drive unit, etc. The transmission 17 is shown coupled to the drive wheel 15, which may be in contact with a road surface.

[0012] In this example embodiment, the hybrid propulsion system also includes an energy conversion device 19, which may include, among other things, a motor, a generator, and combinations thereof. The energy conversion device 19 is further shown coupled to an energy storage device 23, which may include a battery, a capacitor, a flywheel, a pressure vessel, etc. The energy conversion device is operable to absorb energy from the vehicle's motion and / or from the engine and convert the absorbed energy into a form of energy suitable for storage by the energy storage device (in other words, providing generator operation). The energy conversion device is also operable to provide an output (power, work, torque, speed, etc.) to the drive wheel 15 and / or the engine 21 (in other words, providing motor operation).It should be appreciated that in some embodiments, the energy conversion device may include a motor, a generator, or both a motor and a generator, among various other components used to provide the appropriate conversion of energy between the energy storage device and the vehicle drive wheels and / or the engine.

[0013] The illustrated connections between the engine 21, the energy conversion device 19, the transmission 17, and the drive wheel 15 may indicate the transfer of mechanical energy from one component to another, whereas the connections between the energy conversion device 19 and the energy storage device 23 may indicate the transfer of a variety of energy forms, such as electrical, mechanical, pneumatic, hydraulic, etc. For example, torque may be transferred from the engine 21 to drive the vehicle drive wheel 15 via the transmission 17. As described above, the energy storage device 23 may be configured to operate in a generator mode and / or a motor mode.In a generator mode, the system 10 may absorb some or all of the output from the engine 21 and / or the transmission 17, which may reduce the amount of drive output delivered to the drive wheel 15 or the amount of braking torque from the braking system 31, which includes a brake booster 35 with a brake booster pump, for the drive wheel 15. Such operations may be used, for example, to achieve efficiency gains through regenerative braking, increased engine efficiency, etc. Further, the output received from the energy conversion device may be used to charge the energy storage device 23. Alternatively, the energy storage device 23 may receive charging energy from an external energy source 25, such as plugging into a utility power supply or a hydraulic or pneumatic pressure source.In motor mode, the energy conversion device may supply the mechanical output to the engine 21 and / or the transmission 17 using, for example, electrical energy stored in an electric battery or hydraulic energy stored in an accumulator.

[0014] Hybrid propulsion embodiments may include full hybrid systems, where the vehicle can run on just the engine, just the energy conversion device (e.g., motor), or a combination of both. Assist or mild hybrid configurations may also be used, where the engine is the primary torque source, with the hybrid propulsion system acting to selectively provide additional torque, for example, during pedaling or other conditions. Still further, starter / generator and / or intelligent alternator systems may also be used.

[0015] The above with reference to Fig. The various components described in Figure 1 may be controlled by a vehicle control system 41, which includes a control unit 48 having computer-readable instructions for executing routines and subroutines for controlling vehicle systems, a plurality of sensors 43, and a plurality of actuators 53. Selected examples of the plurality of sensors 43 and the plurality of actuators 53 are described in more detail below in the description of the fuel system 101.

[0016] If you now look Fig. 2, there is shown an example system configuration of a multi-cylinder engine, generally shown at 11, used in a propulsion system of a motor vehicle such as the one shown in Fig. 1 shown vehicle may be included.

[0017] The engine may include a plurality of vacuum-utilizing devices or systems coupled to the engine intake system 12, such as an exhaust gas recirculation (EGR) system 14, a crankcase ventilation system 16, a fuel vapor purge system 18, a brake booster 20, and / or a vacuum booster 22. The vacuum booster may, for example, have the construction shown in U.S. Patent 5,291,916. In some examples, one or more of the vacuum-utilizing devices may be coupled to an air horn disposed in the intake system 12 within a throttle and air horn system 45 described below. The fuel vapor purge system 18 may, for example, be coupled to the air horn so that a vacuum created by the air horn may be used to purge fuel from the fuel vapor purge system during selected engine operating conditions.

[0018] The engine system 11 may include a lower portion of the engine block, indicated generally at 26, which may include a crankcase 28 enclosing a crankshaft 30 with an oil sump 32 disposed below the crankshaft. The upper portion of the engine block 26 may include a combustion chamber (i.e., a cylinder) 34. The combustion chamber 34 may include combustion chamber walls 36 with a piston 38 disposed therein. The piston 38 may be coupled to the crankshaft 30 such that reciprocating motion of the piston is translated into rotational motion of the crankshaft. The combustion chamber 34 may receive fuel from fuel injectors (not shown) and intake air from the intake manifold 42 located downstream of the throttle body 44 within a throttle and horn system 45 described below.The engine block 26 may also include an engine coolant temperature (ECT) sensor 46 that is input to an engine control unit 48 (described in more detail below).

[0019] A throttle and horn system 45 (described in more detail below) includes a throttle valve that controls the airflow entering the intake manifold 42 and may be preceded upstream by the compressor 50, followed by a charge air cooler 52. In some examples, the compressor 50 may be equipped with a compressor bypass valve. An air filter 54 may be located upstream of the throttle and horn system 45 and may filter air entering the intake passage 56. A mass air flow (MAF) sensor 58 may be located in the intake system 12 and may be connected to the control unit 48.

[0020] Exhaust combustion gases exit the combustion chamber 34 via an exhaust passage 60 located upstream of a turbine 62. An exhaust sensor 64 may be located along the exhaust passage 60 upstream of the turbine 62. The turbine 62 may be equipped with a wastegate bypassing it. In some examples, the wastegate may be actuated by vacuum. The sensor 64 may be any suitable sensor for providing an indication of the exhaust air / fuel ratio, such as a linear oxygen sensor or UEGO (universal or wideband exhaust oxygen sensor), a dual-state oxygen sensor or EGO, a HEGO (heated EGO), a NOx, HC, or CO sensor. The exhaust sensor 64 may be connected to the controller 48.

[0021] Exhaust gas flowing within the EGR line 66 may be cooled as it flows through the EGR cooler 68, which may be located within the EGR line 66 and upstream of an adjustable exhaust gas recirculation valve 70, followed by an EGR pressure sensor 72, which may be connected to the control unit 48. The adjustable EGR valve 70 controls the flow rate of exhaust gases flowing within the EGR line 66. The EGR valve 70 may be a vacuum-actuated valve. Although this example shows exhaust gas being extracted from downstream of the turbine and supplied upstream of the compressor (low-pressure EGR), it may also be extracted from upstream of the turbine and supplied downstream of the compressor (high-pressure EGR), or combinations thereof, if desired. In another example, the position of the EGR valve 70 may be monitored and controlled by the control unit 48.

[0022] As noted above, various vacuum-utilizing devices or systems may be coupled to an air horn disposed in the intake system 12 within a throttle and air horn system 45 described below. However, it should be noted that in some examples, one or more vacuum-utilizing devices may also be coupled to the engine intake manifold 42, such as a closed crankcase ventilation system.

[0023] In the example of Fig. 2, a closed crankcase ventilation system 16 is coupled to an air horn in the throttle and air horn system 45. The crankcase ventilation system 16 vents air from the crankcase 28 via line 76, which may include a one-way PCV valve 78 to provide continuous venting of gases from the interior of the crankcase 28.

[0024] The PCV line 76 may include a unidirectional oil separator 80 that filters oil from vapors leaving the crankcase 28 before re-entering the intake system 12. The PCV line 76 may also include a vacuum sensor coupled to the PCV system. In the example of Fig. 2, a vacuum sensor 82 is arranged along line 76 between the oil separator 80 and the PCV valve 78. The vacuum sensor 82 may be coupled to the control unit 48.

[0025] As in Fig. 2, an air horn included in the throttle and air horn system 45 may be coupled to the fuel vapor purge system, generally shown at 18. The fuel vapor purge system 18 includes a fuel vapor canister 84 that receives fuel vapors from the fuel tank 86 via line 88. A fuel tank pressure sensor 90 may be disposed along the fuel line 88 and coupled to the control unit 48. An air intake line 92, including an air intake valve 94 connected to the fuel vapor canister 84, allows air to be drawn into the fuel vapor canister 84. The flow of intake air into the fuel vapor canister 84 is controlled by the air intake valve 94.A fuel vapor purge line 96 is connected to the fuel vapor canister 84 and may be coupled to the vent in the throttle and vent system 45 so that the vent can create a vacuum to assist in drawing vapor from the fuel vapor canister 84 via line 96, which may include a fuel vapor purge valve 98 that allows flow control in the fuel vapor purge system. The position of the FVP valve 98 may be monitored and controlled by the control unit 48. As in the example of FIG. Fig. 2, a fuel vapor purge pressure sensor 100 may be disposed within the purge line 96. The FVP sensor 100 may be connected to the control unit 48.

[0026] In some examples, an air horn in the throttle and air horn system 45 may be coupled to the brake booster 20. In one example, the brake booster 20 may be preceded by a vacuum booster 22. In the Fig. 2, the throttle and horn system 45 is coupled downstream to the vacuum booster 22 via a line 102 that supplies a vacuum for the vacuum booster 22, which feeds vacuum-operated actuators generally shown at 104 (e.g., vacuum brakes, HVAC controls, and EGR actuation (such as valve 70)). As in the example of Fig. 2, the brake booster 20 may include a vacuum sensor 106 that may be connected to the control unit 48. When coupled to the brake booster or vacuum booster for vacuum-operated actuators, the horn provides a source of vacuum even when the manifold pressure is boosted above atmospheric pressure, thus lowering the energy threshold of the brake booster or vacuum booster. However, as noted above, in other examples, the brake booster may instead be coupled to the engine intake.

[0027] The control unit 48 is in Fig. 2 as a microcomputer having a microprocessor unit 108, input / output ports 110, an electronic storage medium for executable programs and calibration values, shown in this particular example as a read-only memory chip 112, a random access memory 114, a latch 116, and a data bus. The control unit 48 may receive various signals from sensors coupled to the engine system 11, including a measurement of inducted mass air flow (MAF) from mass air flow sensor 58; engine coolant temperature (ECT) from temperature sensor 46; PCV pressure from vacuum sensor 82; EGR pressure from vacuum sensor 72; exhaust air / fuel ratio from exhaust gas sensor 64; brake booster vacuum from vacuum sensor 106; fuel tank pressure from pressure sensor 90; and / or the fuel vapor purge pressure from the vacuum sensor 100 .The storage medium read-only memory 112 may be programmed with computer-readable data representing instructions executable by the processor 108 to perform the methods described below, as well as other variations that are expected but not specifically listed.

[0028] Fig. 3 - Fig. 5 illustrate example embodiments of the throttle and blast funnel system 45. The throttle and blast funnel system 45 includes a blast funnel coupled to an intake system of the engine and a throttle valve disposed in the intake system adjacent to the blast funnel. A fuel vapor purge system is further coupled to the blast funnel so that the vacuum created by the blast funnel in the intake system can be used to assist fuel vapor purge.

[0029] If you look Fig. Turning to Figure 3, an example embodiment 300 of the throttle and blast funnel system 45 is shown. In this example, a throttle 44 is disposed within the intake system 12 upstream of an blast funnel 47, and a fuel vapor purge system 18 is coupled to the blast funnel 47 via a purge line 96. The purge line 96 is coupled to the blast funnel 47 near a narrow portion or throat 310 of the blast funnel 47 so that the negative pressure created by the blast funnel as air flows through the blast funnel is accessible to the vapor purge system for purge events. Further, the purge line 96 includes a purge valve 98 disposed therein that is operable in response to fuel vapor purge conditions, as described below.

[0030] Furthermore, a variety of sensors may be optionally disposed in the throttle and horn system 45. In some examples, for example, a purge vacuum sensor 308 may be disposed in the throat 310 of the horn 47 (or optionally in the purge line 96) to estimate an amount of vacuum generated by the horn so that the purge valve 98 may be adjusted accordingly during fuel purge events, as discussed below with respect to Fig. 6. In other examples, the throttle and horn system 45 may not include a purge vacuum sensor, and a vacuum created by the horn 47 may be estimated based on an air flow rate through the horn, e.g., as measured by the mass air flow sensor 58, an air temperature, e.g., as measured by a temperature sensor 306 located upstream of or in an inlet of the horn 47, and an air pressure, e.g., as measured by a pressure sensor 304 located upstream of or in an inlet of the horn 47.

[0031] Further, the throttle valve 44 may include a throttle position sensor 302 coupled to a control unit, e.g., the control unit 48, so that a current throttle position may be determined and the throttle valve may be adjusted in response to operating conditions, as described below with respect to Fig. 7 described.

[0032] In the Fig. In the embodiment 300 shown in Figure 3, which includes a large horn or aspirator downstream of the throttle, engine air flows through the horn during engine operation so that vacuum may be available for vapor purging during engine operation, even near wide-open throttle conditions. In this example, because the horn is downstream of the throttle, vacuum would be increased at part load. Benefits of this configuration include increased vacuum availability and reduced cost. However, with this configuration, wide-open throttle performance may be slightly degraded because a pressure drop may exist across the horn that cannot be recovered.Additionally, this configuration can result in increased air volume downstream of the throttle, which can degrade transient torque response in turbocharged engine applications.

[0033] If you look Fig. Turning to FIG. 4, another example embodiment 400 of the throttle and blast funnel system 45 is shown. In this example, a throttle 44 is disposed in the intake system 12 downstream of an blast funnel 47, and the fuel vapor purge system 18 is coupled to the blast funnel 47 via a purge line 96. The purge line 96 is coupled to the blast funnel 47 near a throat 310 of the blast funnel 47 so that the negative pressure created by the blast funnel as air flows through the blast funnel is accessible to the vapor purge system for purge events.

[0034] The Fig. The embodiment 400 shown in Figure 4 is similar to that described above in Fig. 3, except that the air horn is upstream of the throttle body instead of downstream. In embodiment 400, vacuum cannot be increased at part load (but some vacuum may always be available). Furthermore, in this configuration, increased throttle body deposits or throttle body sticking may occur due to fuel vapors passing through the throttle body during purge events. Like embodiment 300, embodiment 400 may have slightly degraded wide-open throttle performance; however, wide-open throttle performance in embodiment 400 may be increased because more packaging and design flexibility may be available to minimize pressure drop across the air horn.Embodiment 400 may provide increased vacuum availability, reduced costs, and may have little or no impact on transient torque response in turbocharged engine applications.

[0035] If you look Fig. Turning to Figure 5, another example embodiment 500 of the throttle and horn system 45 is shown. In this example, one throttle 44 (series throttle) and one horn 47 are arranged in series in a bypass line 502 coupled to the intake system 12 upstream and downstream of a second throttle 67 (parallel throttle) arranged in the intake. Here, the second throttle 67 is parallel to the horn 47. The fuel vapor purge system 18 is coupled to the horn 47 via a purge line 96. The purge line 96 is coupled to the horn 47 near a throat 310 of the horn 47 so that the vacuum created by the horn as air flows through the horn is accessible to the vapor purge system for purge events.

[0036] The Fig. The example shown in Figure 5 shows a throttle valve 44 disposed in the bypass line 502 upstream of the air funnel 47; however, in other examples, the throttle valve 44 may be disposed in the bypass line 502 downstream of the air funnel 47. Further, the second throttle valve 67 may include a throttle position sensor 312 coupled to a control unit, e.g., the control unit 48, so that a current throttle position of the second throttle valve 67 may be determined and the second throttle valve may be adjusted in response to operating conditions, as discussed below with respect to Fig. 7 described.

[0037] The Fig. The embodiment 500 shown in Figure 5 includes an air horn in parallel with one throttle (parallel throttle 67) and in series with another throttle (series throttle 44). In this configuration, under most part-load conditions, the parallel throttle 67 would be substantially closed, allowing substantially all air to flow through the air horn, and the series throttle 44 would be used to control engine torque at part-load. When maximum engine torque or power is requested, the parallel throttle 67 would be opened to avoid the pressure drop across the air horn. Although this configuration may have increased costs associated with inserting two throttles, increased vacuum availability would be achieved, and the impact on wide-open throttle performance may be reduced.

[0038] As noted above, in some examples, various other negative pressure devices or systems may be used with the Fig. 3 - Fig. 5 in addition to or instead of the fuel vapor purge system 18 so that the vacuum created by the air funnel can be available to other devices using vacuum.

[0039] The control logic for embodiments 300 and 400 described above can be implemented using a fairly conventional purge control strategy. The main difference would be that the purge vacuum is not equal to the intake manifold vacuum, and the purge flow rate depends on the purge vacuum. Thus, a sensor, such as sensor 308, could be used to measure the purge vacuum at the throat 310 of the horn or in the purge line 96. However, in some examples, to avoid the cost of a sensor, the purge vacuum can be derived based on the horn dimensions, the airflow through the horn, and the air density (pressure and temperature) at the horn. This could be implemented, for example, as a first-principle equation or based on mapping data for an actual horn.In embodiment 300, the air horn is located downstream of the throttle, so manifold pressure and temperature could be used in the calculation. In embodiment 400, the air horn is located upstream of the throttle, so air intake temperature and pressure (barometric pressure) could be used in the calculation.

[0040] Fig. 6 shows an example method 600 for controlling operation of an engine having a fuel vapor purge system, e.g., the fuel vapor purge system 18, and a throttle and horn system, such as the throttle and horn system 45 described above.

[0041] At 602, method 600 includes determining whether entry conditions are met. For example, it may be determined whether a vehicle is on or off, that is, whether the vehicle is operable or not. In one example, this may be detected by a key command sensor and / or a vehicle motion sensor to determine whether the vehicle is in an engine-on mode or an engine-off mode. Purge conditions may further include detecting engine-on operations, a signal indicating that the canister loading of fuel vapor is above a predetermined threshold, and / or a signal indicating that the fuel tank pressure is above a threshold.

[0042] If entry conditions are met at 602, method 600 proceeds to 604. At 604, method 600 includes directing intake air through a horn coupled to an intake of the engine. For example, air may be directed through throttle 44 and horn 47 so that a vacuum is created and available for fuel vapor purging.

[0043] To adjust an amount of fuel vapor flow delivered to the vent via a fuel vapor purge valve coupled to the fuel vapor purge system, method 600 includes calculating a purge vacuum at 606. As described above, a purge vacuum created by the vent 47 may be based, for example, on an air flow rate through the vent and an air pressure and temperature. As another example, the purge vacuum may be determined based on a sensor reading from a vacuum sensor in the throat of the vent or in the vapor line 96, e.g., sensor 308.

[0044] At 608, method 600 includes calculating a purge valve duty cycle or other control signal based on the purge vacuum determined at 606 and a desired purge flow rate. For example, controller 48 may adjust purge valve 98 to achieve the desired purge flow rate.

[0045] At 610, method 600 includes actuating purge valve 98, and at 612, method 600 includes supplying a fuel vapor flow from the fuel vapor purge system to the vent to purge fuel vapor from the fuel vapor purge system.

[0046] Because the above-described embodiment 500 includes two separate throttle bodies, the control logic for operating the embodiment 500 may be more complex. Specifically, under most part-load conditions, the parallel throttle body 67 may be substantially closed, allowing substantially all of the air to flow through the horn. The series throttle body 44 may then be used to control engine torque at part-load. When maximum engine torque or power is required, the parallel throttle body 67 may be opened to avoid the pressure drop across the horn.

[0047] In particular, Fig. 7 illustrates an example method 600 for controlling operation of an engine having a fuel vapor purge system coupled to embodiment 500 of the throttle and horn system 45, wherein a first throttle and horn are disposed in a bypass conduit coupled to the intake system upstream and downstream of a second throttle disposed in the intake system.

[0048] At 702, method 700 includes determining whether entry conditions are met. For example, it may be determined whether the vehicle is on or off, i.e., whether the vehicle is operable or not. In one example, this may be detected by a key command sensor and / or a vehicle motion sensor to determine whether the vehicle is in an engine-on mode or an engine-off mode. Further, purge conditions may include detecting engine-on operations, a signal indicating that the canister fuel vapor loading is above a predetermined threshold, and / or a signal indicating that the fuel tank pressure is above a threshold.

[0049] If entry conditions are met at 702, method 700 proceeds to 704. At 704, method 700 includes determining whether an engine load is above a threshold. The threshold may be based, for example, on how much airflow can be delivered to the engine by adjusting the inline throttle 44 while maintaining the parallel throttle 67 substantially closed. The threshold may be based on airflow, intake manifold pressure, estimated engine torque, the pressure differential across the inline throttle cap 44, or any combination thereof.

[0050] If the engine load is not above the threshold at 704, method 700 proceeds to 706. At 706, method 700 includes maintaining the parallel throttle substantially closed and adjusting the inline throttle to achieve a desired torque. For example, controller 48 may be configured to maintain the parallel throttle 67 substantially closed and adjust a position of the inline throttle 44 until a desired torque or torque request is met.

[0051] If the engine load is above the threshold at 704, method 700 proceeds to 708. At 708, method 700 includes determining whether the parallel throttle 67 is in a substantially wide open throttle (WOT) position.

[0052] If the parallel throttle 67 is not in a WOT position at 708, method 700 proceeds to 710. At 710, method 700 includes maintaining the inline throttle 44 in a current position and opening the parallel throttle to achieve a desired torque. For example, controller 48 may be configured to maintain the inline throttle 44 in a current position while adjusting the parallel throttle 67 to achieve a desired or requested torque.

[0053] However, if the parallel throttle is in a WOT position at 708, method 700 proceeds to 712. At 712, method 700 includes determining whether additional torque is desired. For example, if the parallel throttle 67 is in a WOT state, the parallel throttle 67 may not be adjustable to achieve any additional torque requirements. Thus, if more torque is desired at 712, method 700 proceeds to 714.

[0054] At 714, method 700 includes opening the inline throttle to meet the additional torque requests. For example, controller 48 may be configured to maintain parallel throttle 67 in a WOT state and adjust inline throttle 44 to meet the additional torque requests.

[0055] Fig. Figure 8 graphically shows example throttle settings in response to engine load changes at a given engine speed for the Fig. 5 shown embodiment 500 as described above with regard to Fig. 7 described.

[0056] In particular, Fig. 8 Throttle position settings for throttle valve 44 (T1), shown as a dash-dot line, and throttle valve 67 (T2), shown as a solid line, during three example engine operating conditions.

[0057] The first example engine operating condition, shown at 802, is when an engine load is less than a threshold a1. During this condition, the first throttle T1 is adjusted at a rate s1 to satisfy a torque request, such as requested by a driver via an accelerator pedal, while the second throttle T2 is maintained in a substantially closed position. Of course, although the rates of throttle position changes described in Fig. 8 are linear, in some examples the rates may be non-linear. Further, these throttle position change rates may depend on the speed of an engine. For example, at increased speed, the throttle position change rates may increase. Further, an amount of throttle position changes may depend on a size or area of ​​the throttle plates in the first and second throttle bodies. For example, throttle body T2 may have a throttle plate with a larger area than the throttle plate in throttle body T1.

[0058] During a second engine operating condition, shown at 804, the engine load is greater than threshold a1 and less than a second threshold a2. Engine load values ​​less than threshold a1 may, for example, be part-load conditions, whereas engine load values ​​greater than a1 may be high-load conditions. Engine load values ​​above second threshold a2 may be additional torque requests beyond what, for example, throttle T1 can adjust to with throttle T1 in a fixed position.

[0059] During the second engine operating condition 804, throttle T1 is held open at a current position, which may depend on engine speed or other engine parameters, while throttle T2 is adjusted at a rate s2 to meet a desired torque. For example, throttle T1 may be held at a throttle position corresponding to engine load a1, and throttle T2 may be opened to meet torque requirements beyond engine load a1.

[0060] At a2, throttle T2 reaches a wide open throttle (WOT) condition or a throttle angle of 100%, thus any additional torque requirements beyond a2 can be met by adjusting throttle T1 at a rate s3.

[0061] In this manner, during part-load conditions, throttle valve T1 is held partially open and adjusted to meet torque requirements so that air flows through air funnel 47 to create a vacuum for use by fuel vapor purge system 18, and the amount of vacuum is increased by the pressure drop across partially open throttle valve T1. During high-load conditions, throttle valve T1 is still held in a fixed partially open state so that air still flows through air funnel 47 to create a vacuum for use by fuel vapor purge system 18, and the amount of vacuum is increased by the pressure drop across partially open throttle valve T1 while throttle valve T2 is adjusted to meet high-load torque requirements.Finally, under very high load conditions, throttle T1 must be opened further to meet the desired engine torque, despite the reduction in available vacuum from the pressure drop across throttle T1.

[0062] Fig. 9 shows example throttle settings in response to pedal position changes, e.g., via a driver applying an accelerator pedal coupled to the engine 11, for the Fig. 5 shows an embodiment 500. In particular, Fig. 9 Example throttle position settings (TP1) at throttle valve 44 (T1) and throttle position settings (TP2) at throttle valve 67 (T2) in response to changes in pedal position (PP) and engine load changes.

[0063] For example, in region 902, the pedal position (PP) increases until an engine load threshold is reached at 904. In region 902, the throttle T1 is opened by an amount to increase airflow to the engine to meet the torque request created by the increase in pedal position. In this region, the throttle T2 is held substantially closed until the engine load reaches a threshold at 904 (e.g., until the engine load a1, which is Fig. 8 is shown).

[0064] Once the engine load reaches the threshold at 904, throttle T1 is held in a current position and throttle T2 is opened by an amount to meet the torque requests after 904 created by the increasing pedal position.

[0065] During a pedal release condition at 906, when the engine load is above the threshold, throttle T1 is held in its current state and throttle T2 is closed until the engine load is below the threshold at 908, at which point throttle T1 is adjusted by an amount to reduce airflow to the engine during the pedal release condition. In some examples, throttle T1 is held in an open position after pedal release to allow air to continue flowing through horn 47 so that a vacuum is still created for use during fuel purge events. However, in other examples, throttle T1 may also be closed after accelerator pedal release, e.g., depending on engine speed and whether the vehicle is in, for example, a trailer towing mode.

[0066] During a pedal-treading condition at 910, when the engine load is below the threshold, throttle T2 is held substantially closed while throttle T1 is adjusted by an amount to meet torque demands created by the increase in pedal position. When the engine load reaches the threshold at 912, throttle T1 is held in its current open position and throttle T2 is adjusted by an amount to meet the torque demands created by the increase in pedal position during high engine loads.

[0067] In this manner, transient engine operating conditions can be met while still allowing air to flow through the air funnel with a pressure drop across throttle T1 to maximize the amount of vacuum available to vacuum-using systems, such as a fuel vapor purge system coupled into an inlet of the air funnel.

[0068] Fig. 10 shows an example method 1000 for adjusting throttle 44 (T1) and throttle 67 (T2) in embodiment 500 in response to a pedal-tapping condition. At 1002, method 1000 includes determining whether a pedal-tapping condition occurs. A pedal-tapping condition may occur, for example, in response to a change in a position of a driver-applied accelerator pedal when a driver requests an increase in engine torque and / or engine speed. If a pedal-tapping condition occurs at 1002, method 1000 proceeds to 1004.

[0069] At 1004, method 1000 includes determining whether an engine load is above a threshold. As noted above, the threshold may be a predetermined engine load threshold, where engine loads less than the threshold are part-load conditions and engine loads above the threshold are high-load conditions.

[0070] If the engine load is below the threshold at 1004, method 1000 proceeds to 1006. At 1006, method 1000 includes maintaining throttle T2 in a substantially closed state such that substantially all air flows through throttle T1 and horn 47. At 1008, method 1000 includes opening throttle T1 an amount to achieve a desired torque requested by pedal position. When the desired torque is achieved at 1010, method 1000 ends. However, if the desired torque is not achieved by the adjustment to throttle T1 at 1010 and the engine load remains below the threshold, then throttle T1 may be opened further to achieve the desired torque. However, if the engine load increases above the threshold at 1004, then the method 1000 proceeds to 1012.

[0071] At 1012, method 1000 includes holding throttle T1 in a current position. For example, throttle T1 may be held open by an amount it was opened to achieve the threshold engine load. At 1014, method 1000 includes opening throttle T2 to achieve the desired torque during the high load condition. If the desired torque is achieved at 1016, method 1000 ends. However, if the desired torque is not achieved at 1016, then throttle T2 may be opened further to achieve the desired torque until throttle T2 reaches a wide-open throttle (WOT) condition at 1018.If throttle T2 is in a WOT condition and the desired torque has not been achieved, then method 1000 at 1020 includes opening throttle T1 further from its current position to achieve the desired torque.

[0072] Fig. 11 shows an example method 1100 for adjusting throttle 44 (T1) and throttle 67 (T2) in embodiment 500 in response to a pedal release condition. At 1102, method 1100 includes determining whether a pedal release condition occurs. A pedal release condition may occur, for example, in response to a change in a position of a driver-applied accelerator pedal when a driver requests a decrease in engine torque and / or engine speed. If a pedal release condition occurs at 1102, method 1100 proceeds to 1104.

[0073] At 1104, method 1100 includes determining whether an engine load is above a threshold. If the engine load is above the threshold at 1104, method 1100 proceeds to 1106. At 1106, method 1100 includes maintaining throttle T1 in its current position. At 1108, method 1100 includes closing throttle T2 by an amount to achieve the desired reduced torque, for example, requested by a driver via an accelerator pedal.

[0074] If the desired torque is achieved at 1110, then method 1100 ends. However, if the desired torque is not achieved at 1110 and throttle T2 is fully closed, then method 1100 includes closing throttle T1 from its current position at 1112 to achieve the desired reduced torque.

[0075] However, if at 1104 the engine load is below the threshold, then method 1100 proceeds to 1114. At 1114, method 1100 includes closing throttle T2 if it was open, or maintaining throttle T2 substantially closed. If the desired reduced torque is achieved at 1116, method 1100 ends. However, if the desired torque is not achieved at 1116 with throttle T2 fully closed, then at 1118, method 1100 includes closing throttle T1 from its current position to achieve the desired reduced torque.

[0076] It should be noted that the example control and estimation routines included herein can be used with various system configurations. The specific routines described herein may represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, and the like. As such, various illustrated acts, operations, or functions may be performed in parallel in the illustrated sequence, or in some cases, omitted. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of explanation and description.One or more of the depicted acts, functions, or operations may be performed repeatedly depending on the particular strategy employed. Furthermore, the described operations, functions, and / or acts may graphically represent code to be programmed into the computer-readable storage medium in the engine control system.

[0077] Again, it should be understood that the systems and methods described herein are exemplary in nature, and that these specific embodiments or examples should not be considered limiting, as numerous variations are contemplated. Accordingly, the present disclosure encompasses all novel and non-obvious combinations of the various systems and methods disclosed herein, as well as any and all equivalents thereof.

Claims

[1] A method for controlling the operation of an engine (21) having a fuel vapor purge system (18), comprising: Directing intake air through a first throttle valve (44, T1) and an air funnel (47) arranged in a bypass line (502) coupled in parallel around a second throttle valve (67, T2) arranged in the inlet; in response to an operating condition, supplying a fuel vapor flow from the fuel vapor purge system (18) to an inlet of the air funnel (47); characterized by Adjusting an amount of fuel vapor flow supplied to the inlet of the air funnel (47) via a fuel vapor purge valve (98) coupled to the fuel vapor purge system (18), wherein the amount of fuel vapor flow supplied to the inlet of the air funnel (47) is adjusted based on an air flow rate through the air funnel (47) and an air temperature and pressure. [2] The method of claim 1, wherein the air funnel (47) is coupled to the bypass line (502) downstream of the first throttle valve (44, T1). [3] The method of claim 1, wherein the air funnel (47) is coupled to the bypass line (502) upstream of the first throttle valve (44, T1). [4] The method of claim 1, further comprising, in response to the engine load being less than a threshold (a1), adjusting the first throttle (44, T1) to achieve a desired torque while maintaining the second throttle (67, T2) substantially closed. [5] The method of claim 1, further comprising, in response to an engine load being greater than a threshold (a1) when the second throttle (67, T2) is not in a wide open throttle (WOT) condition, adjusting the second throttle (67, T2) to achieve a desired torque while maintaining the first throttle (44, T1) substantially fixed in a partially open condition. [6] The method of claim 1, further comprising, in response to an engine load being greater than a threshold (a2) when the second throttle (67, T2) is in a substantially wide open throttle (WOT) state, adjusting the first throttle (44, T1) to achieve a desired torque while maintaining the second throttle (67, T2) in a wide open state. [7] The method of claim 1, wherein the engine (21) is part of an electric hybrid powertrain. [8] A method for controlling the operation of an engine (21) having a fuel vapor purge system (18), comprising: Directing intake air through a first throttle valve (44, T1) and an air funnel (47) arranged in a bypass line (502) coupled in parallel around a second throttle valve (67, T2) arranged in the inlet; in response to an engine load being less than a threshold (a1), adjusting the first throttle valve (44, T1) to achieve a desired torque while keeping the second throttle valve (67, T2) substantially closed, and in response to an engine load being greater than a threshold (a1), when the second throttle valve (67, T2) is not in a wide open throttle (WOT) state, adjusting the second throttle valve (67, T2) to achieve a desired torque, while the first throttle valve (44, T1) is held fixedly in a partially open state; and in response to a fuel vapor purge condition, supplying a fuel vapor flow from the fuel vapor purge system (18) to an inlet of the air funnel (47). [9] The method of claim 8, further comprising adjusting an amount of fuel vapor flow supplied to the inlet of the air funnel (47) via a fuel vapor purge valve (98) coupled to the fuel vapor purge system (18), wherein the amount of fuel vapor flow supplied to the inlet of the air funnel (47) is adjusted based on an air flow rate through the air funnel (47) and an air temperature and pressure. [10] The method of claim 8, wherein the air funnel (47) is coupled in the bypass line (502) upstream of the first throttle valve (44, T1). [11] The method of claim 8, wherein adjusting the first (44, T1) and second (67, T2) throttles in response to an engine load being greater than a threshold (a2) when the second throttle (67, T2) is in a substantially wide open throttle (WOT) state comprises adjusting the first throttle (44, T1) to achieve a desired torque while maintaining the second throttle (67, T2) in the wide open state. [12] A system for a prime mover (21) comprising: a first throttle valve (44, T1) and an air funnel (47) arranged in a bypass line (502) coupled in parallel around a second throttle valve (67, T2) arranged in the inlet; and a fuel vapor purge system (18) coupled to an inlet of the air funnel (47); a control system configured to control the first and second throttle valves as follows: in response to an engine load being less than a threshold (a1), adjusting the first throttle (44, T1) to achieve a desired torque while keeping the second throttle (67, T2) substantially closed, and in response to an engine load being greater than a threshold (a1), when the second throttle (67, T2) is not in a wide open throttle (WOT) state, adjusting the second throttle (67, T2) to achieve a desired torque while holding the first throttle (44, T1) fixed in a partially open state. [13] The system of claim 12, wherein the first throttle valve (44, T1) is located upstream of the air funnel (47). [14] The system of claim 12, wherein the first throttle valve (44, T1) is located downstream of the air funnel (47). [15] The system of claim 12, wherein the fuel vapor purge system (18) is coupled to the inlet of the air funnel (47) via a fuel vapor purge line (96), and wherein the fuel vapor purge line (96) includes a purge valve (98) disposed therein. [16] The system of claim 12, wherein the engine (21) is part of a hybrid electric powertrain. [17] The system of claim 12, wherein the engine (21) uses stop-start to reduce idle time. [18] The system of claim 12, wherein the engine (21) uses one or more of cylinder deactivation, variable camshaft timing, variable valve lift, turbocharging, or supercharging.

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